Why do coins have a reeded edge? Almost everyone who has ever held a coin is familiar with the fine grooves on the edge. Their history begins with people who cut precious metal from coins.
Cooper here! 🐾 Johan from Sweden sent me this question: “Cooper, why do so many coins have a reeded edge? And is it true that Isaac Newton invented it?” I started by investigating with my nose. A Krugerrand was lying on the table in the office, and its edge felt like a very small comb. The trail leads back to 17th-century London, to coin cutters, and to the man who described the laws of gravity.
Why the silver disappeared from the edge
Before machine minting became widespread, coins were struck by hand for centuries. A worker placed a metal blank between two dies and struck it with hammer blows. The result was rarely perfectly round, and the edge was not uniform.
This is precisely what the coin clippers exploited. They cut or filed small amounts of silver from the edges, collected the metal, and redistributed the lighter coins. With a single coin, the loss was hardly noticeable, but with thousands of coins, a considerable amount of precious metal accumulated.
In England, clipping royal coins was considered high treason and could be punished by death. Nevertheless, the practice was difficult to curb. By the 1690s, English silver coins were in a severe crisis. Many old coins were far too light due to clipping and wear, and people distrusted the money in their pockets. [1]
How England protected the coin’s edge
The solution was a raised edge that makes tampering visible. If a coin has a groove, pattern, or writing on its edge, any damaged area shows that someone has removed metal.
Attempts at machine minting existed in England long before Newton. Under Elizabeth I, the Frenchman Eloy Mestrell established his own mint with a screw press in the Tower of London from the early 1560s. His coins looked considerably better than the hand-struck ones, but operating the machines was comparatively expensive. His mint closed in 1572. Mestrell then turned to counterfeiting himself and was probably hanged a few years later. [2]
The decisive change came after the restoration of the monarchy. Under the direction of the French coin technician Pierre Blondeau, new machines were introduced to the mint in the Tower, which also allowed for the design of coin edges. [3] The first machine-struck Crowns were issued at the end of 1662. Half Crowns and Shillings followed in 1663, and the smaller silver denominations over the course of the following decade. Crowns and Half Crowns received edge lettering , while the edges of the other denominations were designed differently depending on the coin type. [4] [5]
The most famous edge inscription was DECUS ET TUTAMEN, Latin for “ornament and protection”. The words come from Virgil’s Aeneid, and the writer John Evelyn is said to have suggested them to the king. The inscription decorated the coin and also served as a security feature, because alterations to the edge were more easily detectable. [4] [6]
The saying has survived for centuries. It was still printed on issues of the round British pound coin, which was introduced in 1983. Ironically, this very coin lost its status as legal tender on October 15, 2017, because it was too easy to counterfeit. According to the Royal Mint, about one in thirty round pound coins in circulation was considered a fake. [7]
The problem with the old coins
The new technology didn’t solve the problem immediately. The old, hand-struck silver coins remained legal tender and could still be clipped. Those who had the choice spent the lighter, clipped coin and kept the new, full-size coin at home.
Economic historians link this behavior to Gresham’s Law. It describes how higher-quality money can be hoarded, melted down, or taken abroad when bad and good money circulate at the same face value. This is exactly what happened in England in the 1690s. [1]
Enter Isaac Newton
In January 1696, the English Parliament passed the “Act for Remedying the Ill State of the Coin of the Kingdom,” which mandated the Great Recoinage. All old silver coins were to be withdrawn, melted down, and re-minted with a protected rim. [8]
On March 19, 1696, Chancellor of the Exchequer Charles Montagu informed Newton that he was to be appointed Warden of the Royal Mint . Montagu described the position as well paid and not so demanding as to require more time than Newton could spare. In April 1696, Newton took up his post at the Tower of London. [9]
The new minting was already underway at this time, but progress was slow. Newton took the supposedly quiet position very seriously. He studied the mint’s operations, analyzed the minters’ work, and helped to significantly increase production. At the end of 1699, he became Master of the Mint and remained so until his death in 1727. [1] [9]
Newton also personally pursued counterfeiters and coin clippers. He questioned witnesses, worked with informants, and systematically collected evidence. [9]
Newton vs. William Chaloner
His most famous opponent was William Chaloner, one of the most skilled forgers of his time. Chaloner publicly attacked the Mint. In 1697, he published a pamphlet addressed to the House of Commons entitled “The Defects in the present Constitution of the Mint,” in which he accused the Royal Mint of serious abuses. [10]
Newton responded with an investigation. Over a considerable period, he gathered statements and evidence against Chaloner. The forger was convicted of high treason and hanged in Tyburn on March 22, 1699.
What’s wrong with the popular Newton legend
It is often said that Isaac Newton invented the reeded coin edge. This is a misconception. When Newton arrived at the Royal Mint in 1696, England had already been minting coins with protected edges for more than three decades, and the first machine experiments dated back some 130 years.
I’m still a young dog, but I have a clear opinion on this. The true story is better than the legend. New technology alone wouldn’t have changed much as long as the old coins remained legal tender and counterfeiters were rarely punished. Newton, with his more efficient organization of the minting process and consistent prosecution, played a crucial role in making the new monetary system work. 🐾
Newton and the path to the gold standard
Newton also left his mark on gold. As Master of the Mint, he wrote an opinion on the ratio of gold to silver on September 21, 1717. In December of the same year, the value of the gold guinea was fixed at 21 shillings. [9]
This valuation favored gold over silver. Silver increasingly flowed out of Great Britain, and gold became ever more important for the British monetary system. Many historians see this as a step towards a de facto gold standard, even though the legal development took decades.
From Newton to Soho Mint
The technology continued to develop. Starting in 1788, Matthew Boulton established the Soho Mint near Birmingham, which is considered the world’s first steam-powered mint. There, too, precisely manufactured coins were intended to be more difficult to counterfeit. The more accurately the diameter, weight, design, and edge could be controlled, the more difficult it became to alter a coin undetected. [11]
Why coins are still reeded today
Modern circulating coins contain hardly any silver or gold. Nevertheless, many of them have a milled or decorated edge, and there are several reasons for this.
A distinctive edge can make counterfeiting more difficult. The German 2-euro coin combines fine milling with the edge inscription UNITY AND JUSTICE AND FREEDOM. Different edges also help with differentiation by touch, which is particularly important for blind and visually impaired people. Therefore, adjacent denominations of euro coins have different edges. The 20-cent coin has a smooth edge with seven indentations in its shape, known as the “Spanish Flower”. [12]
Sometimes an edge design remains due to tradition. The American dime was made of silver until 1964. In 1965, the US Mint removed the silver; since then, it has been minted from copper-nickel layers on a copper core. [13] The reeded edge was retained, however, as was the case with the quarter.
What the rim means for collectors of gold coins
Even modern gold coins like the Krugerrand, Maple Leaf, and Libertad have a milled edge. With the Krugerrand, the number of grooves can differ between the investment and proof versions. However, the milling alone is not sufficient to determine whether a coin is genuine. We explain how to do this in the article “Testing the Authenticity of Gold Coins .”
The edge also counts in grading.
Damage to the edge or raised rim can reduce the value of a coin. In English, these are referred to as “edge nicks” and “rim nicks”.
Since 2008, NGC has used the EdgeView Holder. Four supports hold the coin, so that a large part of its edge remains visible even in the slab. Therefore, anyone buying a high-quality or top-pop coin can also examine the edge, not just the obverse and reverse. [14]
Frequently asked questions about the grooved edge
Who invented the reeded coin edge?
There is no single inventor. Machine minting was tested in England from the 1560s onwards, and under Charles II it became permanently established in the 1660s. Isaac Newton did not arrive at the Royal Mint until 1696.
Did Isaac Newton invent the fluted edge?
No. When Newton Warden became of the Royal Mint, coins with protected edges had been in use in England for decades. However, Newton played an important role in the Great Recoinage and in the prosecution of counterfeiters.
Why were coins trimmed?
Historical silver and gold coins had a high metal value. Small amounts of precious metal could be cut or filed off irregularly shaped, hand-struck coins. The metal was sold, while the lighter coin continued to circulate.
Why does a ridged surface protect against pruning?
The reeding makes tampering visible. If metal is removed from the edge, part of the pattern is missing, and the coin stands out.
What is the technical term for the grooved edge?
In German, the terms “Riffelung” or “Riffelrand” are used. In English, “reeded edge” is the precise term for an edge with regular grooves. The frequently used “milled edge” is broader, as “milled coinage” originally referred generally to machine-made coins.
Stay curious, and next time take a look at the edge too. Until the next collector’s question! 🐾
Professor Cooper ⭐
Sources
[1] University of Oxford, Newton and the Mint : The Mint, a Brief Introduction. On the coinage crisis of the 1690s, the ongoing re-coinage and Newton’s reorganization.
[2] Royal Mint Museum : Tudor Half-Sovereign. On Eloy Mestrell’s screw press in the Tower, its operating costs, its closure in 1572 and its subsequent fate.
[3] Museums Victoria Collections : Coin, Crown, Charles II, Great Britain, 1663. On the minting on the new machine under the direction of Peter Blondeau and on the edge lettering.
[4] Royal Mint Museum: Charles II. On the first machine-struck Half Crowns and Shillings 1663 , the smaller denominations and the edge lettering on Crown and Half Crown.
[5] The Royal Mint: 1662 Charles II First Bust Rose Below Crown . On the issue of the first machine-struck Crowns at the end of 1662 and on the sequence of the subsequent denominations.
[6] Harvard Law Review Forum: Decus et Tutamen . On the edge inscription, on Virgil and John Evelyn, and on the continued existence of the old coins.
[7] The Royal Mint: £1 Coin Designs and Specifications . On the occasion of the end of the round pound on 15 October 2017.
[8] University of Oxford, Newton and the Mint: The Great Recoinage . On the parliamentary decision of January 1696 and on Blondeau’s techniques.
[9] Royal Mint Museum: Isaac Newton, Warden and Master of the Royal Mint . On Montagu’s letter of 19 March 1696, Newton’s term of office and his report of 21 September 1717.
[10] Nature: Isaac Newton, Crime Investigator . With reference to Chaloner’s work “The Defects in the Present Constitution of the Mint” from 1697.
[11] Historic England: When Soho Led the World . About the Soho Mint as the first steam-powered mint.
[12] Austrian National Bank: Common sides of the euro coins . On the edge designs of the euro coins and the Spanish flower.
[13] United States Mint: Dime . On the removal of the silver in 1965 and on the copper-nickel plating.
[14] NGC: EdgeView Holder . On the introduction in 2008 and on the visibility of the edge.
About the authors
Professor Cooper
Cooper is Wasserthal RareCoin.Store’s black Labrador and something of a junior member of staff in the numismatic office. In the Gold Coin Collector Questions section, he answers questions sent in by collectors from all over the world, and in Cooper’s Coin Academy , he’s learning the ins and outs of numismatics step by step. He has a good nose for things, and his knowledge grows with every question. The texts written in Cooper’s name are researched, written, and professionally reviewed by our team. 🐾
Larissa Wasserthal
Larissa Wasserthal is a numismatics expert at Wasserthal RareCoin.Store and a business developer at TriaPrima GmbH. She focuses primarily on modern gold coins, certified collector coins, and their authenticity, condition, and provenance. She manages the collectors’ questions editorially with Cooper and verifies historical and numismatic information using sources such as the Royal Mint, museums, and universities. Her goal is to explain complex topics in a way that empowers collectors to make confident decisions when buying, building, and transferring their collections. You can learn more about her work on Larissa Wasserthal’s page at RareCoin .